diff --git a/cores/arduino/HardwareSerial.h b/cores/arduino/HardwareSerial.h
index 5674e57a..8f1aba87 100644
--- a/cores/arduino/HardwareSerial.h
+++ b/cores/arduino/HardwareSerial.h
@@ -26,7 +26,7 @@
 class HardwareSerial : public Stream
 {
   public:
-    virtual void begin(unsigned long);
+    virtual void begin(uint32_t);
     virtual void end();
     virtual int available(void) = 0;
     virtual int peek(void) = 0;
diff --git a/cores/arduino/Reset.cpp b/cores/arduino/Reset.cpp
index 67ef9e32..e0d830ff 100644
--- a/cores/arduino/Reset.cpp
+++ b/cores/arduino/Reset.cpp
@@ -23,7 +23,11 @@
 extern "C" {
 #endif
 
+#if !defined(__clang__) || defined(__mips__)
 __attribute__ ((long_call, section (".ramfunc")))
+#else
+__attribute__ ((section (".ramfunc")))
+#endif
 void banzai() {
 	// Disable all interrupts
 	__disable_irq();
diff --git a/cores/arduino/USB/CDC.cpp b/cores/arduino/USB/CDC.cpp
index dea6bd2b..4b93cf91 100644
--- a/cores/arduino/USB/CDC.cpp
+++ b/cores/arduino/USB/CDC.cpp
@@ -336,7 +336,7 @@ int32_t Serial_::readBreak() {
 	return ret;
 }
 
-unsigned long Serial_::baud() {
+uint32_t Serial_::baud() {
 	return _usbLineInfo.dwDTERate;
 }
 
diff --git a/system/CMSIS/CMSIS/Include/core_cmFunc.h b/system/CMSIS/CMSIS/Include/core_cmFunc.h
index 88819f9d..69289534 100644
--- a/system/CMSIS/CMSIS/Include/core_cmFunc.h
+++ b/system/CMSIS/CMSIS/Include/core_cmFunc.h
@@ -300,6 +300,13 @@ static __INLINE void __set_FPSCR(uint32_t fpscr)
 #elif defined ( __GNUC__ ) /*------------------ GNU Compiler ---------------------*/
 /* GNU gcc specific functions */
 
+/* C++17 removes register keyword */
+#if __cplusplus >= 201703L
+# define DEPRECATED_REGISTER
+#else
+# define DEPRECATED_REGISTER register
+#endif
+
 /** \brief  Enable IRQ Interrupts
 
   This function enables IRQ interrupts by clearing the I-bit in the CPSR.
@@ -402,7 +409,7 @@ __attribute__( ( always_inline ) ) static __INLINE uint32_t __get_xPSR(void)
  */
 __attribute__( ( always_inline ) ) static __INLINE uint32_t __get_PSP(void)
 {
-  register uint32_t result;
+  DEPRECATED_REGISTER uint32_t result;
 
   __ASM volatile ("MRS %0, psp\n"  : "=r" (result) );
   return(result);
@@ -429,7 +436,7 @@ __attribute__( ( always_inline ) ) static __INLINE void __set_PSP(uint32_t topOf
  */
 __attribute__( ( always_inline ) ) static __INLINE uint32_t __get_MSP(void)
 {
-  register uint32_t result;
+  DEPRECATED_REGISTER uint32_t result;
 
   __ASM volatile ("MRS %0, msp\n" : "=r" (result) );
   return(result);
@@ -591,6 +598,8 @@ __attribute__( ( always_inline ) ) static __INLINE void __set_FPSCR(uint32_t fps
 
 #endif /* (__CORTEX_M == 0x04) */
 
+#undef DEPRECATED_REGISTER
+
 
 #elif defined ( __TASKING__ ) /*------------------ TASKING Compiler --------------*/
 /* TASKING carm specific functions */